Manufacture of propeller blades



June 12, 1945,

C. A. BRAUCHLER MANUFACTURE OF PROPELLER BLADES Filed July 7, 1941 2 Sheets-Sheet 1 a SN QRWN Q N \h M %N N R M WN N 3% g} MWNN N N [Mr/05A Zia/1M! June 12, 1945.

c. A. BRAUCHL'ER MANUFACTURE OF PROPELLER BLADES Filed July '7, 1941 2 Sheets-Sheet 2 Patented June 12, 1945 f ..Mlsmm nmnorsm m' p v oharl s-a;maneuver-matri ony v Application-Jilly},1941,;Setiztl No dilletfili,

7 mama: (GLQFIEPQ) .The invention relates to the manufacture of propeller blades for airplanes, and more -.particularly 'to-ra novelmethod of making hollow, metal 'blades 'iormed by forging operations. I

"The general object of the invention contemplates an improved construction of. hollow metal mopellerblade with integral, internal reinforcing means, and a novel method of forming theblade byiorging operations. I l

A further object :of the inventionisato provide a cinethod .of making a hollow zmetalrpropeller blade which is internally reinforced :by integral, longitudinal reinforcing ribs.

:Another object is to provide amethod ofianak+ ing :a hollow metal-propeller blade formed" from a single plate of metal having a taperedplongi- 'tudinal corrugation .formed through its me'dian line to form the leading edge'of the propeller blade. w Still another object is to provide for th'e manufuture of thelblade from such a. plate in which longitudinal ribs are formed on opposite sides of "the central corrugation and ladapted' to be ,:welded together at'their butting edgeswhen the plate is bent along said median corrugation. I

A further" object is to provide'for making a hollowpropeller blade in whichthe opposite side edges of the plate blank are welded orotherwise connected'together. Y

*Astill further object of the invention is to prowide a novel method of forming a propeller-blade which consists in forging a fiat blahk'fro'm' a metal-plate, the blank being tapered 'ln th'icl't-n es s *from the hub and toward the-tip andprovid'ed with a central longitudinal tapered corr igati'on in one surface'and longitudinal ribs'uponits other- .surface, the blank being then'heated'ar i'd oilrved longitudinally from end to end'to conform 'to the desired contour of the leading edgeof the finished Q blade after which the blank is folded or bent upon itself'along its medial line-and the opposite edges of the blank are welded together and theimeetlng edges of the ribs are welded together iormiriga 'hollow reinforcedmetal bladeioi thefdesired conftour. .The. above objects, together with others, which will .be app rent from, the drawings and;.following description, .or which may beilater referred to, may be. attained .by' constructing the improved zhollowimetal propeller bladein the-mannerhereinaiterdescribed in detail, and illustratedinthe accompanying drawingsjn which y Figur l isa, plan view ofthe. forged blank from a a ion-gamma;station-M the blank showninFig. l; H; l

, 13,:amelevationiofthehubiend of the that,

V r.Flg. 4,satransverse5cross-sectional view'through the blank, taken as on the line 4%4, Fig. 1 1 ;Fig.--5, .a:transverse cross-sectional viewthrough i-therblanh taken asson theline 5-5, Fig. 1'; "Fig. 6, a transverse cross-sectional view of the 1blank-,-:taken;$s:on the. line 6:6,.=Fig.i 1;.

'10 Flg..-i'l, a,-transverse cross-sectionalview of-lthe -=-blank,taken'asonthellneh-Laig.1; ,1 1; Fig. 8, a transverse cross-sectionalview of the -blank;=*takenasontheline:8-:B;Fig.1;

-.:;.:Flg. .=9.,- awtmnsverse crossasectional view or the xFigflfll'ai-transveme cross-sectionalviewof the blank, taken as on the1 1ine.l0* .l'0,,Fig. l; I l 1 :l-ha longitudinal "edge elevation :of 1' the blank fatter th'e same has been longitudinally :bent

20 orcambered 'tt0 0b'nf01m to the "desired contour -01therleadmgsedgesofzthe:ilnished blade; "j ":1 -ll2, :a gala-n view :ofsaw'com'pleted propeller blade normed iii). accordance with the invention;

completed propeller, taken as on the line H H, Fig. 113 f. Fig. 215,19, transversessectional 'IVi'BW through the 16,12. transverse sectional view through-the i'bl'a'de, takeneasonithe line li -"l6, Fig'l'llr f l a transverse .aseoti'onal view through "the blade; Utakenas "on the line fi -11,- Fig. l 1;

so I Figs-1185a transverse sectional view throughthe z bladeltakemas'on'the-line 18-4-8, Fig. 11; it

k tFig. 19;:a transverseisectional view through the blade, taken as on the line l 9-! 9, Fig. 11;

20,. a. :transverse sectional *view' through {no it'he .rbladeyatakenpals;:'on *the .line 20-20., Fig. 1 1

Fig. 21, a transverse sectional viewthroug' h the :bladentakenmsohzthe line! l--2 l-,Figl l1.

.-.numera1s' irfe'r to "similar parts. throughoutithe drawmgs. a

The improved propeller blade to which thein- -lventilmiilertainsimay beiiorrned of steel or other -suitablevmeta1rof conventional exterior form he'- ing aohhollow lconstruotion' provided "with longioo :tudinalzintemalireinforoing i'ibsi v The blade maywbe rcrmeu rrom a rectangular steel plate or heavy sheet of the gen'er'a l shape indlc'ated'sby the'oot anfioashoiitiinezs in -Fig. 1. g p v elateror sheetis'neated-to forging temwhich-the'lmprovedpropeller:bladeistiormed; #65 .perature md-zrollfdorged in-a machineof the metal being preferably thickened throughout the,

tapered portion of the corrugation 25 as indi cated at 28.

Straight parallel longitudinal ribs 29 and30 are formed on the opposite side of the blank and v cavo-convex corrugation on one side thereof, said corrugation being tapered from one end of the blank toward the other end thereof, then curving the entire blank longitudinally to shape said corrugation to the desired contour of the leading edge of the blade, then bending the blank upon itself along said corrugation and forming the blank so as to substantially flatten the same on opposite sides of aid corrugation and bringing the opposite edges of the blank into contact with each other, and uniting said edges.

2. The method of making a hollow metal pro- ;qpeller blade which consists in forming a generally fiat blank with a medial, longitudinal conon each side of the center thereof and extend ing from a point near the hub and to a point spaced from the tip end of the blank, these ribs being tapered toward the tip'end of the-blank as best showninFig.2.

The blank is then sheared to the'outline shown in full lines in Fig. 1 forming the similar oppositesideedgesiil. i i

The blank thus formed 'is' then heated and placed in suitable forging dies where it is pressed or hammered to the form shown -in' Fig. 1'1-,'the entire blankbeing given a longitudinal cambered curve indicated generally at'32,conforming to the desired contour of the leading edge of the completed blade. i

The next step in the method of forming the blade consists in bending or folding the 'cambered blank shown in Fig. 11 upon itself along its medial longitudinal line, that is, through the axis of the corrugation 26. I

This bending or forming may be performed by first reheating the blank, or if desired, "the blank may be bent cold. This bending or forming op-= eration is accomplished by. pressing or hammering the preferably heated, cambered blank of Fig. IL-folding it upon itself along the central corrugation 26 and substantially flatteningthe blank on opposite sides of said corrugation; thus' bringing'opposite edges of the blank intocontact with each other. 1

cave-convex corrugation on one side thereof, said corrugation being tapered from one end of the blank toward the other end thereof, and with integral ribs upon each side of the corrugation,

. which ribs are parallel with the axis of the corblank longitudinally to shape said corrugation to the desired contour of the leading edge ofthe blade, then bending the blank upon itself along said corrugation, and forming the blank so as to substantially flatten the same on opposite sides The edges 3| of the blank are brought into contact with each other and welded together as indicated at 3la in Figs. 14't0 21, inclusive, and

the edges of the ribs 29-29 and 30 30 are brought into contact with each other and welded together as indicated at and 34,'res'pectively.

The reinforced tapered corrugation 26 thus forms the leading edge of the blade 35 shown in Figs. 12' to 21, inclusive, while-the welded edges 3| of the blank form the opposite edge cf'the walls permanently united at their meeting 'edges' to form the other edge of the I claim:

blade; "4

1. The method of making a 'hollow metal propeller blade which consists in forming a generally flat blank with .a medial, longitudinal conof said corrugation bringing the opposed edges of said ribs into contact with each other and bringing the opposite edges of the blank into contact with each other, and uniting said edges of the .ribs, and uniting said edge of the blank.

3. The method of making a hollow metal propeller blade which consists in forming a, generally. flat blank with a medial, longitudinal concavo-lconvex'corrugation on one side thereof, said corrugation being tapered from one end of the blank toward the other end thereof, and with integral ribs upon each side of the corrugation. which ribs are parallel with the axis of the corrugation and equally spacedlaterally therefrom and tapered in the same direction as said-corrugation and positioned on the opposite side of the blank, from said corrugation, then curving the entire blank longitudinally to shape said corrugation to the desired contour-of the leading edge of the blade, then bending the blank upon itself along said corrugation, and forming the blank so as to substantially flatten the same on opposite sides of said corrugation bringing the opposed edges of said ribs into contact with each other and bringing the opposite edges of the blank-into contact with each other, and uniting said edges of the ribs, and uniting said edges of the blank, I

,tourof the leading edge of the blade, then bending thev blank upon itself along said corrugation and forming the blank so as to substantially flatten the same on opposite sides of said corrugation bringing the opposite edges of the blank into contact with each other, and uniting said edges.

5. The method of making a hollow metal propeller blade which consists in forming a generally iiat blank tapered in thickness from one end toward the other end with a medial, longitudinal concavo-convex corrugation correspondingly tapered, and with integral ribs upon each side ofthe corrugation, which ribs are parallel with said corrugation to the desired contour of the leading edge of the blade, then bending the blank upon itself along said corrugation, and forming the blank so as to substantially flatten the same on opposite sides of said corrugation bringing the opposed edges of said ribs into contact with each other and bringing the opposite edges of the blank into contact with each other, and uniting said edges of the ribs, and uniting said edges of the blank.

6. The method of making a hollow metal propeller blade which consists in forming a generally flat blank with a medial, longitudinal, con,- cavo-convex corrugation on one side thereof, said corrugation being tapered from one end of the blank toward the other end thereof, then curving the entire blank longitudinally to shape said corrugation to the desired contour of the leading edge of the blade, then reheating the blank and forming it by bending the blank upon itself along said corrugationso as to substantially flatten the blank on each side of the corrugation and bringing-opposite edges of the blank into contact with each other and uniting said edges.

'7. The method of making a hollow metal propeller blade which consist in forming a generally flat blank with amedial, longitudinal, concave-convex corrugation on one side thereof, saidcorrugation being tapered fromone end of the blank toward the other end thereof, and with integral ribs upon each side of the corrugation and on the opposite side of the blank from said corrugation, then curving the entire blank longitudinally to shape said corrugation to the desired contour of the leading edge of the blade, then 

